It seemed nearly every aisle and international pavilion at the Specialty Food Association’s Summer Fancy Food Show last week had at least one olive oil booth. Countries including Israel, Italy, Spain, Greece and Turkey shared tiny tasting spoons full of the liquid fruits of their labors.

For Lori Konstantopoulos and her family, it’s a labor of love that goes back 10 generations. The American wife of a Greek man, Konstantopoulos raised her kids around the family’s olive grove in the foothills of Mount Taygetos in Siamou, Greece, where the fruit has been grown in the same place for 500 years, using sustainable, biodiverse practices that don’t deplete the land’s nutrients.

Recently, the family has ramped up its marketing efforts to sell its Euphoria brand oil through more distribution channels, including a few U.S. shops like Eli Zabar’s and Ideal Cheese in New York City. The oil is also available for sale on the brand’s website, and purchases are shipped directly from the company to the customer to ensure freshness. And while it’s not yet at the point where it’s selling all of its own oil, the family is also part of a village co-op that can source up to five times more product, she said.

Not to be outdone by their international peers, California’s producers put their own oils on display, with support from the California Olive Oil Council, which puts its members’ products through both chemical tests and a tasting panel that sips the oils “neat” and denotes notes from a wide array of descriptors from hints of artichoke and cinnamon to tropical and woody flavors.

California Olive Ranch launched in 1998 and spent about a decade getting systems in place to be able to produce the enough quality oil to go national, said Sales & Marketing VP Mike Forbes. The oil is cold-pressed, extra-virgin olive oil from three company owned ranches and 60 sustainable family farms that range from Chico down to the Napa Valley.

Today, the company’s extra-virgin oil in distinctive dark-green rectangular bottles is available at more than 5,000 stores across the U.S., including Whole Foods and Stop & Shop. And while it might look like one of the higher-end options on the shelf, it’s actually one of the more affordable choices. That was by design, Forbes said, since people often try to save their priciest oils for special occasions, forgetting that, unlike a fine wine, oil doesn’t get better with age — it only gets rancid. “We could have done a more expensive price, but we wanted people to be comfortable using it every day.”

You can tell about how long you’ve been holding onto that bottle of California Olive Ranch because each one has a press date on the label — a requirement for California oils that bear the certification of the California Olive Oil Council, said education coordinator Nancy Ash. California oils are fresher for U.S. residents by virtue of the logistics involved, she said. Pressing and bottling takes place in the fall and early winter, and oils from Europe begin arriving in April at the earliest, she said.

Once bottled, oils have a shelf life of about year, 18 months at the most, before they begin spoiling, Ash said. Life can get even more confusing for olive oil fans when you consider that some imported brands in the supermarket are the result of blended oils from different places, which makes it harder to tell how long they’ve been in the bottle and how long you have before the oil begins to go rancid.

Euphoria’s Greek oils also have a press date on the bottle, but it’s generally less common to find a date of any kind on imported oils, Ash said, and it has even proved difficult to get many domestic producers to date the bottles. “The producers have been resistant because people look at it like the dates on milk,” she said. “The answer is to educate the public.”